For quite some time, electrostatic chucks have been utilized in plasma-based or vacuum-based semiconductor processes such as etching, CVD, and ion implantation, etc. A typical electrostatic chuck, for example, comprises a dielectric layer positioned over a conductive electrode, wherein a semiconductor wafer is placed on a surface of the electrostatic chuck. During semiconductor processing, a clamping voltage is typically applied between the wafer and the electrode, resulting in electrostatic forces that adhere the wafer to the surface of the electrostatic chuck.
In many applications, however, declamping or un-sticking the wafer from the chuck surface is a concern. For example, after the clamping voltage is turned off, the wafer typically “sticks” to the chuck surface for a considerable amount of time, wherein the wafer cannot be adequately removed by typical wafer lifting mechanisms. In one previous solution, using a typical wafer lifting mechanism where the wafer is lifted from the surface in one fell swoop can result in the wafer “popping” from the surface of the chuck. This “pop” can occur with such force the wafer is not only freed from the chuck, but also becomes dislodged from the wafer lifting mechanism. This can ultimately result in the wafer tumbling to the ground, which can break the wafer or riddle the wafer with defects to such an extent to render it is unsalvageable.
Therefore, a need exists in the art for declamping systems and methods which are capable of adequately removing a wafer from an electrostatic chuck.